[[TracNav(802.11/TOC)]] = Receiver Characterization = The IEEE 802.11 Standard specifies a minimum receiver sensitivity that all 802.11 devices must achieve. This sensitivity is specified as a receive power (in dBm) in which a device must achieve no worse than a 10% packet-error-rate (PER) for PPDU receptions of 1000 octets. The receiver minimum input sensitivity requirements are specified in Section 18.3.10.2 of 802.11-2012 and are reproduced here: ||= Rate =||= Modulation / Coding =||= Minimum Sensitivity (dBm) =|| || 6 Mbps || BPSK 1/2 || -82 || || 9 Mbps || BPSK 3/4 || -81 || || 12 Mbps || QPSK 1/2 || -79 || || 18 Mbps || QPSK 3/4 || -77 || || 24 Mbps || 16-QAM 1/2 || -74 || || 36 Mbps || 16-QAM 3/4 || -70 || || 48 Mbps || 64-QAM 1/2 || -66 || || 54 Mbps || 64-QAM 2/3 || -65 || The values specified in this table recognize that higher rate transmissions require higher SNR (and therefore higher delivered power) than lower rate transmissions. == Receiver Sensitivity Test == To test the Mango 802.11 Reference Design Rx PHY against these measures, we use the [http://www.keysight.com/en/pd-326092-pn-N4010A/wireless-connectivity-test-set?&cc=US&lc=eng Keysight N4010A Wireless Connectivity Test Set] to generate known-good 1000 octet transmissions and deliver those transmissions to WARP v3 at a specified power. Then, we use the [wiki:802.11/wlan_exp WLAN Experiments Framework] to measure PER. || [[Image(experimental_setup.jpg, width=600)]] || || [[Image(setup.png, width=600)]] || || '''Experimental Setup''' || === Methodology === 1. Construct PPDU waveforms in MATLAB for each PHY rate that have the following characteristics: a. 1000 octet PPDU length (i.e., a 972 byte payload + 14 byte MAC header + 4 byte FCS) a. 10 different scrambling sequence start points to generate waveforms with different peak-to-average-power (PAPR) features 1. Load each waveform in to the N4010A's volatile memory as segment files. 1. Create N4010A sequence files that send each waveform segment 1000x in a row 1. Use [https://warpproject.org/docs/mango-wlan-exp/node.html#statistics-commands WLAN Experiments Statistics] to determine how many of the transmissions were fully received with a good FCS. We have used the above steps determine the Mango 802.11 Reference Design's receive sensitivity across 7 different WARP v3 kits and RF interfaces. || [[Image(rx_sensitivity, width=800)]] || The above plots shows the results of this experiment. In particular, notice the receive powers that cross the 10% PER horizontal line -- these can be compared directly to the minimum sensitivity values specified by the standard. Specifically, ||= Rate =||= Modulation / Coding =||= Minimum Sensitivity (dBm) =||= '''Mango 802.11 Sensitivity (dBm)''' =||= '''Difference''' =|| || 6 Mbps || BPSK 1/2 || -82 || '''-85''' || '''3dB better than minimum''' || || 9 Mbps || BPSK 3/4 || -81 || '''-83''' || '''2dB better than minimum''' || || 12 Mbps || QPSK 1/2 || -79 || '''-83''' || '''4dB better than minimum''' || || 18 Mbps || QPSK 3/4 || -77 || '''-81''' || '''4dB better than minimum''' || || 24 Mbps || 16-QAM 1/2 || -74 || '''-78''' || '''4dB better than minimum''' || || 36 Mbps || 16-QAM 3/4 || -70 || '''-75''' || '''5dB better than minimum''' || || 48 Mbps || 64-QAM 1/2 || -66 || '''-71''' || '''5dB better than minimum''' || || 54 Mbps || 64-QAM 2/3 || -65 || '''-69''' || '''4dB better than minimum''' ||